Rapamycin (Sirolimus) Geriatric (65+) Caregiver Administration Guidance

What the label actually covers

Sirolimus is a prescription mTOR inhibitor immunosuppressant [1]. Its two approved uses are prevention of organ rejection in kidney transplant recipients aged 13 and older, and treatment of lymphangioleiomyomatosis (LAM) [1]. There is no approved indication for aging, longevity or healthspan, so any use for those purposes sits outside the label [1].

In the label's kidney transplant safety study, participants had a mean age of 46 and ranged from 15 to 71; those results do not describe patients in their 80s [1]. The boxed warning also states that sirolimus is not recommended in liver or lung transplant patients [1].

Compounded rapamycin is a separate issue. Compounded drugs are not FDA-approved, and FDA does not verify their safety, effectiveness or quality before they are marketed [4]. The 48-week PEARL trial in healthy, normative-aging adults used compounded rapamycin [2].

Giving the dose: what the label specifies

For Rapamune's approved uses, the label specifies once-daily dosing, taken consistently with or without food [1]. It says not to crush, chew or split the tablets, and it directs use of the oral solution for patients unable to take tablets [1].

If cyclosporine is part of the regimen, the label says to take Rapamune 4 hours after cyclosporine, because cyclosporine increases sirolimus concentrations [1]. The label states that grapefruit juice must not be taken with Rapamune or used to dilute it [1].

The once-weekly schedule studied in the PEARL aging trial is not a labeled regimen [1][2].

What caregivers should watch for at home

Infection. The boxed warning describes increased susceptibility to infection and the possible development of lymphoma and other malignancies, particularly of the skin, as consequences of immunosuppression [1]. New fever, cough, shortness of breath or a skin change that is not healing are worth reporting promptly.

Swelling and wound healing. The label lists fluid accumulation including peripheral edema, lymphedema, pleural effusion, ascites and pericardial effusions, and describes impaired or delayed wound healing in patients receiving Rapamune [1]. New leg swelling, rapid weight gain or a wound that stalls should be reported rather than attributed to age or position.

Angioedema. Rapamune has been associated with angioedema, and the label notes that combining it with drugs that also cause angioedema, such as ACE inhibitors, may increase that risk [1]. Swelling of the lips, tongue or face, especially with trouble breathing or swallowing, is an emergency.

Lipids. In the label's kidney transplant trials, hypercholesterolemia occurred in 43 to 46 percent and hypertriglyceridemia in 45 to 57 percent of patients on Rapamune, against 23 percent for each in placebo controls [1].

Blood counts. In the label's kidney transplant safety table, thrombocytopenia occurred in 14 percent on 2 mg daily, 30 percent on 5 mg daily and 9 percent on placebo, and anemia in 23, 33 and 21 percent respectively [1]. Those are transplant doses, not the low intermittent doses used in longevity trials.

Mouth sores. Stomatitis is among the most common adverse reactions in the LAM study, at 20 percent or more [1]. The label also lists interstitial lung disease and proteinuria as warnings [1].

Vaccines. The label says to avoid live vaccines during treatment [1]. CDC's adult schedule recommends one influenza vaccination each year and lists two doses of recombinant zoster vaccine for adults with immunocompromising conditions [5].

Interactions that matter in a household

Sirolimus is a substrate of both CYP3A4 and P-glycoprotein, so drugs that act on either pathway change its blood levels [1]. The label says to avoid strong inducers (rifampin, rifabutin) and strong inhibitors (ketoconazole, voriconazole, itraconazole, erythromycin, telithromycin, clarithromycin) [1].

It advises caution with modulators that could raise sirolimus concentrations: bromocriptine, cimetidine, cisapride, clotrimazole, danazol, diltiazem, fluconazole, letermovir, HIV and hepatitis C protease inhibitors, metoclopramide, nicardipine, troleandomycin and verapamil [1]. Diltiazem and verapamil are blood pressure and heart-rate drugs, so the full medication list matters [1].

Agents that could lower sirolimus concentrations include carbamazepine, phenobarbital, phenytoin, rifapentine and St John's wort [1]. Cannabidiol can raise sirolimus levels, and the label says a Rapamune dose reduction should be considered when the two are taken together [1]. Grapefruit juice is prohibited, for drinking and for dilution [1].

Liver and kidney considerations

Hepatic impairment raises sirolimus exposure substantially: area under the curve increased by 43 percent in mild, 94 percent in moderate and 189 percent in severe impairment, and the label reduces the maintenance dose by about one third in mild-to-moderate and about one half in severe impairment [1].

On the kidney side, the label lists decline in renal function with long-term cyclosporine plus Rapamune, and proteinuria as a labeled warning [1].

What the older-adult studies actually showed

A 2018 pilot trial randomized 25 generally healthy adults aged 70 to 95 to rapamycin 1 mg daily or placebo, with 11 rapamycin and 14 placebo participants completing at least 8 weeks [3]. Reported side effects in the rapamycin group were facial rash (one person), stomatitis (one) and gastrointestinal issues (two), and the rapamycin group had statistically significant decreases in hemoglobin, hematocrit, red cell count, RDW, MCV and MCH [3]. The trial had no clinical benefit endpoint for longevity [3].

The 48-week PEARL trial gave healthy, normative-aging adults placebo or 5 mg or 10 mg compounded rapamycin once weekly [2]. Adverse and serious adverse events were similar across groups, the primary outcome — visceral adiposity — did not change (p=0.942), and blood biomarkers stayed within normal ranges [2]. Lean tissue mass and self-reported pain improved in women on 10 mg, and emotional well-being and general health improved on 5 mg [2]. The authors called the regimen relatively safe over 48 weeks and stated that efficacy was not established [2]. Neither trial measured lifespan.

One often-cited immune study in elderly volunteers tested RAD001 (everolimus), a different mTOR inhibitor, not sirolimus [6].